SANTA ANA, Calif.—People who mistakenly believe they are registered as domestic partners in California have the same rights as those who fulfilled terms of the state’s Domestic Partner Act, an appeals court ruled.

There is “no sound reason” to deprive persons of their rights if they “reasonably believed” they had registered as domestic partners, a panel of the state 4th District Court of Appeals ruled May 6.

That reverses an Orange County court ruling that denied a gay man’s 2006 petition to dissolve a domestic partnership. The man and his partner signed and notarized a 2003 partnership agreement, but the partner contended it was never filed with the California secretary of state and therefore no partnership had been formed.

The reversal allows Darrin Ellis, 35, of Newport Beach, to try to show he had a good-faith belief there was a registered domestic partnership in order to seek property and other assets acquired during his relationship with David Arriaga, 44.

The appellate decision cited a doctrine that “a person’s reasonable, good-faith belief that his or her marriage is valid entitles that person to the benefits of marriage, even if the marriage is not, in fact, valid.”

That doctrine “extends to those who intended to register their domestic partnerships…and had a reasonable, good-faith belief that the registration had occurred,” the decision said.

California bans same-sex marriage but allows same-sex civil unions or domestic partnerships that confer most of the same legal rights, such as access to family benefits at work and the ability to adopt children as a couple. About 49,000 couples are registered.